Organic ester synthesis



Patented Feb. 20, 1951 ORGANIC ESTER SYNTHESIS William F. Gresham andRichard E. Brooks, Wilmington, Dcl., assignors, to E. I. du Pont deNemours & Company, Wilmington, Del., a corporatlon of Delaware NoDrawing. Application February 11, 1949, Serial No. 75,968

This invention relates to the synthesi of organic oxygen-containingcompounds and more particularly to the synthesis of esters of organiccarboxylic acids by reaction between organic compounds containingoleflnic unsaturation, carbon monoxide and alcohols. This appl n is acontinuation-in-part of our copending application 5. N. 712,736, filedNovember 27, 1946, which in turn, is a continuation-in-part of ourapplication S. N. 629,698, flied November 19, 1945, both of whichapplications have been abandoned. This application is also acontinuation-in-part of our copending application 8. N. 636,262, whichwas filed on December 20, 1945, now Patent No. 2,526,742.

In the Vail patent, U. S. 1,979,717, it is disclosed that esters can beprepared by reaction between olefins, carbon monoxide, and aliphaticalcohols in the presence of certain catalysts, e. g. ammonium chloride,phosphoric acid, etc. The Vail patent expressly states that it isdesirable to avoid the presence of metallic carbomrls in carrying outthe reaction. Certain metal halide type compounds, such as the halidesof calcium, barium, strontium, sodium, potassium, calcium, rubidium,lithium, tin, iron, cobalt, nickel, bismuth, manganese, lead, titanium,zinc, cadmium, molybdenum and boron have also been found to be catalystsfor somewhat similar syntheses, such as the synthesis of propionic acidfrom ethylene, carbon monoxide and water, but in all instances the onlycatalysts which have given promising results heretofore in suchsyntheses have been halide type catalysts, which, in general, areexcessively corrosive to metals under the reaction conditions.

An object of this invention is to provide a method for the synthesis ofesters of organic carboxylic acids in the presence of catalysts whichare not excessively corrosive upon the pumps and reaction vesselsemployed in the process. A further object is to provide a commerciallyfeasible process for the manufacture of esters of organic carboxylicacids from readily available and very inexpensive starting materials.Other objects and achievements of the invention will appear hereinafter.

These objects are accomplished in accordance with the invention byreacting an organic compound containin non-aromatic olefinicunsaturation with carbon monoxide and an alcohol at elevatedtemperatures and pressure in the presence of a catalyst containingcobalt as an essential ingredient. It is to be understood that thecobalt may be present in the free metallic 18 Claims. (Cl. 260-483)state or may be combined with other substances in the form of alloys orcompounds, as, for example, cobalt carbonyl. No halide need be present;in fact, preferred catalysts include organic compounds of cobalt, whichgive outstanding results in the absence of cobalt halides or any othersource of halogen acid. In specific embodiments, and by way ofillustration, the invention contemplates the synthesis of esters inaccordance with the .following equations in the presence of the hereindisclosed catalyst:

CH|=CH3 Union C0 --9 CHgCHrCOOCH (2) 2CH1=CH1+ CH CK-+200 -bCHaCHsCCHjCHgCOOCH The latter equation represents a new type of reactionwhich, in accord with the present invention, takes place under hereindisclosed conditions, particularly at very high pressures, e. g.pressures in excess of 1500 atmospheres. Analogous reactions take placewith oleflnic reactants other than ethylene and with alcohol reactantsother than methanol.

In certain embodiments the invention comprises reacting an organiccompound containing non-aromatic oleflnic unsaturation with carbonmonoxide and a primary alcohol 01' the formula ROH (It being an alkyl,or aralkyl group), at elevated temperatures and pressures in thepresence of the cobalt-containing catalyst, and in the absence of othercatalysts for the reaction (e. g. cobalt halides), whereby compounds ofthe formula acylOR are produced.

It is generally preferred to carry out the reaction between olefiniccompounds, carbon monoxide and alcohols in accordance with theinvention, in the absence of any substantial quantity of halide, or freeinorganic acidic catalysts. It is thus frequently desirable to employmetallic cobalt catalysts, or cobalt carbonyls (this term carbonyl beingused throughout the specification and the appended claims to include allforms of carbonyls and carbonyl hydrides. e. g.

004((10) n and CoH(Co) 4) or soluble cobalt salts, in the absence ofinorganic acid catalysts. such as hydrogen halides or boron fluoride.The organic or inorganic salts (not including halides) which areeifective as catalysts for the reaction, may, of course, have an acidicreaction towards indicators. Organic salts of cobalt, such a ooor not itis converted to carbonyl during the proc-' ess.- It is also to beunderstood, for example, that cobalt carbonyl, it it is introduced assuch or formed as an intermediate, may be converted in whole or in partto more complex compounds of cobalt by reaction with alcohols, etc.,under the conditions of the synthesis. When such a reaction of cobaltcarbonyl occurs, numerous organic compounds of cobalt may be produced,but this does not detract from the value of the process since all of theorganic compounds of cobalt are operative in the practice of theinvention; thus, it is possible to recover the cobalt in the form of anorganic or inorganic compound of cobalt after the reaction is complete,and to reuse such recovered cobalt compounds in a subsequent reactionbetween the alcohol, olefinic compound, carbon monoxide.

The unsaturated compounds containing olefinic unsaturation which may beused in accordance with this invention are the olefinic hydrocarbons andother organic compounds containing a (i. e. at least one) non-aromaticdouble bond between the carbon atoms. Suitable examples of suchcompounds are the olefinic hydrocarbons themselves, e. g. ethylene,alkyl-substituted ethylene (such as propylene, butene-2, isobutylene,pentene-l, tetramethyl ethylene, diisobutylene, triisobutylene,tetraisobutylene and cracked gasoline fractions) cyclohexene, butadiene,isoprene, polymerized dienes, styrene, alpha-methyl styrene, vinylcyclohexene, pinene, limonene, mixed olefins or olefin fraction obtainedby cracking and/or dehydrogenation of petroleum, cyclohexadiene,dicyclopentadiene; unsaturated oxygenated compounds such as allylalcohol, allyl acetate, allyl ethers, methallyl alcohol, vinyl acetate,furane, methyl methacrylate, methyl acrylate, methallyl propionate,methyl oleate, oleic acid, methyl vinyl ketone, methyl vinyl ether,cyclohexene carboxylic acids, esters of cyclohexene carboxylic acids,methallyl methacrylate, acrolein; and, in general, the unsaturatedhydrocarbons, esters, ethers, carboxylic acids, amides, aldehydes, andketones containing non-benzenoid olefinic unsaturation, especially theunsaturated organic compounds as above described which do not containelements other than carbon, hydrogen, oxygen or nitrogen.Halogen-containing olefinic compounds which do not form halide catalystsmay also be employed. It is sometimes desirable to employ polymerizationinhibitors with the readily polymerizable reactants.

The alcohols which may be employed in the practice of the inventioninclude the primary monohydric and primary polyhydric alcohols such as.methanol, ethanol, n-propanol, n-butanol, isobutanol, allyl alcohol,lauryl alcohol, myricyl alcohol, nitroalkanols, chlorohydrin,methoxyethanol, methoxymethoxyethanol, ethylene glycol, glycolmonoesters, glycerin, polyvinyl alcohol, triethanolamine, benzylalcohol, monoethanolamine, hydroxyacetic acid, methyl hydroxyacetate,and the like; and cycloaliphatic primary alcohols such as,hexahydrobenzyl alcohol, betacyclohexyl ethanol, betaor gamma-cyclohexylpropanol, etc.

The reaction is preferably conducted by heating the mixture of organiccompound containing olefinic unsaturation, carbon monoxide, and thealcohol in a suitable pressureresistant vessel in the presence of acobalt catalyst. The simple mono-olefin hydrocarbons having from 2 to 4carbon atoms per molecule generally do not require as high a pressure asis required by the highly branched olefins, such as tetramethylethylene.In general, however, the pressure should be within the range of about 50to 3000 atmospheres, or even higher, the maximum pressure being limitedonly by the strength of the retaining vessel. The simple olefinichydrocarbons, particularly ethylene, propylene, and iso butylene may bereacted, according to the invention, very satisfactorily at pressureswithin the range of 200 to 1500 atmospheres. Pressures exceeding 1000atmospheres are frequently required for the highly branched olefiniccompounds. If oxo-substituted esters are desired, pressures in excess-of1500 atmospheres, suitably about 3000 atmospheres, or even higher,should be employed. Oxo-substituted esters are produced, for example,when the pressure is 8000 atmospheres.

The amount of catalyst which may be employed in the practice of theinvention may be varied Widely but is generally about 0.05% to about 30%of the total weight of the reaction mixture. If desired, the aforesaidcatalysts may be employed in combination with inert materials orsupports such as charcoal, silica, aluminum, kiesel'guhr, pumice, etc.,or promoters such as ThOa, Mn, etc. In particular embodiments, thecobalt content of the catalysts disclosed herein may be replaced atleast in part by nickel.

The reaction between the olefinic compound, carbon monoxide, and alcoholmay be conducted either batchwise or continuously. When solid catalystsare employed, they may be used in the form of a fixed bed or they may beconducted through the reaction vessel along with the reactants.Alternatively, solid catalysts may be employed in a finely dividedfluidized state or they may be suspended in the reaction mixture. Thereaction may be conducted either in the liquid or the vapor phase. Whensoluble forms of catalyst such as cobalt salts of organic carboxylicacids or cobalt carbonyl are employed, they may be introduced assolutions in one of the reactants or in a diluent. Recovered forms ofthe catalyst are especially effective and may be recycled.

The relative proportions of reactants employed may be thestoichiometricaliy required quantities, although other proportions maybe employed if desired. Excellent results are obtained when the moleratio of olefim'c compound:C0:alcohol is about 1:1:1 to about 1:20:1.

If desired, any inert liquid may be employed as a reaction medium.However, the reaction may be conducted satisfactorily in the absence ofany added medium. Examples of suitable inert organic solvents which maybe employed as reaction media are cyclohexene, xylene, benzene,saturated hydrocarbons, esters and the like. To' suppress the water-gasreaction it is frequently preferred to employ carbon dioxide as adiluent.

of the following examples.

Example 1.A mixture containing 144 grams of methanol, 21 gramsot-ethylene and grams of finely divided metallic cobalt wa heated for 90minutes at a temperature of 240 to 260 C.

Example 3.-A mixture containing 144 grams 7 of methanol, 42 grams ofisobutylene and 5 grams of cobalt propionate was heated for one hour ata temperature of 240 to 255 C. under a pressure of 675 to 725atmospheres of carbon monoxide. The conversion to methyl isovalerate was11.8%.

Example 4.A mixture containing 138 grams of ethanol, 10.5 grams ofethylene and grams of cobalt propionate was heated for 20 minutes at atemperature of 180 to 215 C. under a pressure of 400 to 705 atmospheresof carbon monoxide. The conversion to ethyl propionate was 41%, over andabove the maximum conversion that could have been obtained by reactionbetween the cobalt propionate and ethanol.

Example 5.-A mixture containing 150 grams of methanol, 14 grams ofethylene and 20 grams of cobalt propionate was heated at a temperatureof 240 to 250 C. for 11 minutes under a pressure of 660 to 705atmospheres of carbon monoxide. Distillation of the resulting productgave a methyl propionate-methanoi azeotrope which corresponded to a49.5% conversion to methyl propionate.

Example 6.A mixture containing 160 grams of methanol, 31.5 grams ofpropylene, and 5 grams of cobalt propionate was heated for 35 minutes at225 to 240 C. under a pressure of 610 to 725 atmospheres of carbonmonoxide. Conversion to methyl n-butyrate was 23.6

Example 7.-A mixture of 186 grams of ethylene glycol, 28 grams ofethylene and 5 grams of cobalt propionate was heated for 1 hour at 250to 300 C. under a pressure of 545 to 765 atmospheres of carbon monoxide.The. conversion to ethylene glycol monopropionate was 40%.

Example 8.A 400 cc. silver-lined high pressure shaker tube, charged with.64 grams of methpressure dropped to 580 atmospheres. The liquid productwas extracted with water to remove sure shaker tube was charged with 128grams of methanol and 5 grams of cobalt-copper-thoria catalyst(100:3:18). It was then pressured with carbon monoxide to 400atmospheres and heated to 200 C. 650 atmospheres). Butadiene wasinjected at approximately cc. per hour for 1.5 hours, raising thepressure to 810 atmospheres, and reaction was continued for anadditional 7.5 hours at 198 to 200 C. The conversion of butadiene tomethyl-4-pentenoate was 16%, and the yield was ca. 80%.

. Example 10.-A 400 cc. silver, high pressure shaker tube was chargedwith 64 grams or met anol and 5 grams of cobalt (reduced cobaltousoxide). It was pressured with carbon monoxide to 400 atmospheres andthen heated to 198 C., which caused the pressure to increase to 540atmospheres. Isoprene was im'ected at approximately 40 cc. per hourduring 1.5 hours, which raised the pressure to 690 atmospheres; thereaction was then continued for 7.5 hours at 197 to 200 C. The productwas washed with water to remove methanol and filtered to remove catalystresidue. The product boiling at 143 to 145 C. comprised the methyl esterof a C6 unsaturated fatty acid and 27% of unsaponifiable byproduct.

weight of heel 10 grams, cobalt content 0.57

gram) was processed with 120 grams of methanol and 21 grams of propylenefor 10 minutes at 235 to 240 C. with carbon monoxide under a pressure aof 800 atmospheres in a silver-lined shaker tube.

Distillation of the resulting product gave 39 grams of methyl butyrateand 12 grams of a distillation heel containing 0.54 gram of cobalt. Thisdistillation heel could be recycled and recovered repeatedly in thesynthesis of successive quantities of methyl butyrate by the sameprocedure.

Example 12.-A 400 cc. silver-lined, high pressure shaker tube wascharged with 128 grams (4 mols) of methanol, 38 grams (0.33 mol) ofmethyl 4-pentenoate, and 5 grams of reduced, unsintered cobalt oxidecatalyst, pressured with carbon monoxide to 450 atmospheres and heatedat 238 to 242 C. for 9.5 hours. During this period the pressure fellfrom 665 atmospheres to 525) atmospheres. The reactor wascooled,pressure was released, and the liquid product was discharged.This product was steam distilled and the steam volatile oil wasseparated, washed with water and dried over calcium chloride; weight 26grams. esters of 6-carbon dibasic acids (B. P. 114 to 123 C./30 mm.)corresponding to a conversion of 17%. Hydrolysis of the mixed estersyielded a methanol and filtered to remove catalyst residues.

102.2 to 103.2 C. and gave no depression in melt-' ing point when mixedwith an authentic specimen of the amide of 4-pentenoic acid.

Example 9.--A 400 cc. silver-lined, high presmixture of dibasic acidswhich were separated by fractional extraction and crystallization togive a major proportion of adipic acid, the remainder consisting of moresoluble acids which were not identified.

Example 13.-A mixture consisting of 32 grams methanol, 14 gramsethylene, and 2 grams. cobaltous acetate was heated at200 to 210 C. withcarbon monoxide under 3000 atmospheres pres sure for 30 minutes.Distillation of the resulting product gave 14.9 grams of methyl4-oxohexanoate.

Example 14.-A mixture consisting of 30 grams Distillation yielded amixture of methyl e 7 oi isopropyl alcohol, 28 grams oif ethylene, andlgram oi 002(): was heated at 200 to 215 C. with carbon monoxide under3000 atmospheres pressure for 60 minutes. A mixture of products wasobtained, including 7.0' grams of a hem-ester of the formulaCHsCHaCOCHaCI-IaCOOCI-HCI-Is) 2 Example 15.-A mixture consisting of 28grams of isobutylene, 32 grams of methanol, 1.0 gram hydroquinone, 1.0gram Co(CO) I, and 0.6 gram iodine was heated at 295 to 300 C. for 30minutes with carbon monoxide under a pressure of 3000 atmospheres.Distillation oi the resulting mixture gave 16.5 grams oi. methylisovalerate, B. P. 1l2-118 C.

Example 16.--A mixture or 93.1 grams of lauryl alcohol, 7 gramsethyleneand 1 gram Co:(CO)u was heated for 30 minutes at 210' C. withcarbon monoxide under a pressure of 44,000 to 45,000 pounds per squareinch. Distillation of the resulting product at 5 to 7 mm. pressure gavea series of fractions, indicating that the product was quite complex.Some of the fractions solidified on condensation at about roomtemperature. The fraction boiling at 125 to 220 C./7 mm. had an esternumber of 59.5 and a carbonyl number of 78.3.

Example 17.A mixture of 70 grams of 1- decene, 32 grams of methanol, and1 gram CO:(CO)| was heated for one hour at 200 to 215 C. under apressure of 41,000 to 45,000 pounds per square inch. Distillation of theresulting mixture gave 59 grams of a methyl hendecanoate fraction, B. P.70 to 85 C./2 to 3 mm. A distillation heel (weight 6.5 grams) remained;this contained solid ingredients, asample of which had a carbonyl numberof 120.6.

Example 18.-A pressure vessel ischarged with 0.2 part of cobaltcarbonyl, 3.18 parts of methanol, 1.33 parts of ethylene, and 1.56 partsof 8 organic carboxylic acids which comprises heating a non-aromatichydrocarbon containing oleflnic unsaturation with carbon monoxide and aprimary alcohol at a temperature in the range of from 150 to 500 C.,'under a pressure or at least 50 atmospheres, in the presence of acatalyst which has been introduced into the reaction mixture in the formor a substance selected from the class consisting of metallic cobalt.cobalt oxides, cobalt metal carbonyls. and cobalt salts oi. organiccarboxylic acids, and thereafter separating from the resulting mixturean organiccarboxylic ester formed by the ensuing reaction between thesaid hydrocarbon, carbon monoxide; and primary alcohol, the said processbeing car-* ried out in the absence of any other catalyst tor the saidreaction.

2. A process for the production oi. esters of organic carboxylic acidswhich comprises heating ethylene with carbon monoxide and methanol at atemperature in the range of from 175 to 375 C., under a pressure inexcess of 1500 atmospheres, in the presence of a catalyst which 7 v hasbeen introduced into the reaction mixture alkane having from 1 to 4carbon atoms per molcarbon monoxide and heated for 18 hours at 200 I C.under a pressure of 8500 to 7500 atmospheres. Two and seventy-sevenhundredths parts of gas is absorbed. The vessel is washed out withmethanol and the resulting solution is first centriiuged to remove solidmatter and then distilled to give the following fractions:

A. 9.63 parts, B. P. 61 to 66 C./760 mm. B. 0.57 part, B. P. 196 to 201C./760 mm. C. 0.73 part, B. P. 40 to 102 C./0.5 mm.

Fraction A had a saponiflcation equivalent of 560, corresponding to 1.51parts of ester calculated as methyl propionate. Treatment of 0.8

1 part of A with 2.4-dinitrophenylhydrazine yielded 0.07 part of diethylketone 2,4-dinitrophenylhydrazone, M. P. 151 to 152 C. alone or mixedwith an authentic sample. This indicated the presence of 0.27 part ofdiethyl ketone in A. When 0.15 part of B was treated at 25 with 75 partsof 2N hydrochloric acid saturated with 2,4- dinitrophenylhydrazine, two2,4-dinitrophenylhydrazones were formed. The first (0.051 part) afterrecrystallization from methanol, melted at 105 to 106 C. alone or mixedwith the 2,4-dinitrophenylhydrazone of a substance which was obtainedfrom a run made at lower pressure and identified as methyl4-ketohexanoate. The second (0.035 part), M. P. 186 to 187 C., afterrecrystallization from xylene, was soluble in 5% sodium bicarbonatesolution and was similarly identified as 4-ketohexanoic acid2.4-dinitrophenylhydrazone.

We claim:

1. A process for the production of esters of ecule. at a temperaturewithin the range of from 175 to 375 C. under a pressure within the rangeof 1500 to 8500 atmospheres in the presence of a cobalt carbonylcatalyst, whereby an ester of 4- oxohexanoic acid is produced, andthereafter separating the said ester from the resulting mixture.

4. The process of claim 3 in which the said hydroxyalkane is methanoland the said ester of 4-oxohexanoic acid is methyl 4-oxohexanoate.

5. A process for the poduction oi esters of organic carboxylic'acidswhich comprises heating a monoleflnic hydrocarbon having from 2 to 4carbon atoms per molecule with carbon monoxide and a primary alcohol inthe presence of an organic compound 01' cobalt as the sole catalyst, ata temperature in the range of from to 500 C. under a pressure of from 50to 3000 atmospheres and recovering from the resulting mixture the esterproduced by the ensuring reaction.

6. A process for the production of organic oxygen-containing compoundswhich comprises heating ethylene with carbon monoxide and a primaryalcohol in the presence of a catalytic quantity of cobalt propionate ata temperature in the range of from 150 to 500C. under a pressure of from50 to 3000 atmospheres, in the absence of a halide catalyst, andrecovering from the resulting mixture the ester produced by the ensuingreaction.

7. A process for the production of esters of organic carboxylic acidswhich comprises heating a non-aromatic hydrocarbon containing olefinicunsaturation with carbon monoxide and a primary alcohol in the presenceof a catalyst which has been introduced into the reaction vessel in theform of a substance selected from the class consisting of metalliccobalt, cobalt oxides, cobalt metal carbonyls, and cobalt salts oforganic carboxylic acids, at a temperature in the range of from 150 to500 C., under a pressure from 50 to 3000 atmospheres, and thereafterseparating from the resulting mixture the organic carboxylic acid esterformed by the ensuing reaction between the said hydrocarbon, carbonmonoxide, and primary alcohol, the said process being carried out in theabsence of any other catalyst for the said reaction.

8. A process for the production of esters of organic carboxylic acidswhich comprises heating ethylene with carbon monoxide and a primaryalcohol in the presence of a catalyst which has been introduced into thereaction vessel in the form of a substance selected from the classconsisting of metallic cobalt, cobalt oxides, co'- balt metal carbonyls,and cobalt salts of organic carboxylic acids, at a temperature in therange of from 150 to 500 C., under a pressure from 50 to 3000atmospheres, and thereafter separating from the resulting mixture theorganic carboxylic acid ester formed by the ensuing reaction, saidprocess being carried out in the absence of any other catalyst for thesaid reaction.

9. A process for the production of esters of organic carboxylic acidswhich comprises heating an olefinic hydrocarbon having from 2 to 4carbon atoms per molecule with carbon monoxide and a primary alcohol inthe presence of a catalyst which has been introduced into the reactionvessel in the form of a substance selected from the class consisting ofmetallic cobalt, cobalt oxides, cobalt metal carbonyls, and cobalt saltsof organic carboxylic acids, at a temperature in the range of 150 to 500C., under a pressure of 50 to 3000 atmospheres, whereby a reaction.product containing ester is produced, said process being carried out inthe absence of any other catalyst for the said reaction.

10. A process for the production of esters of organic carboxylic acidswhich consists essentially in introducing into a reaction vessel aprimary aliphatic alcohol, a non-aromatic hydrocarbon containingolefinic unsaturation, carbon monoxide, and 0.05% to about 30% byweight, based on the weight of the reaction mixture, of a catalyst fromthe class consisting of metallic cobalt, cobalt oxides. cobalt metalcarbonyls, and cobalt salts of organic carboxylic acids, heating theresulting mixture at a temperature in the range of 175 to 375 C. under apressure of from 50 to 3000 atmospheres, whereby an organic ester isproduced by reaction between the said hydrocarbon, carbon monoxide andalcohol, and thereafter separating the said organic ester from theresultant reaction product.

11. A process for the production of esters of organic carboxylic acidswhich comprises heatin ethylene with carbon monoxide and a primaryalcohol in the presence of a catalyst which has been introduced into thereaction vessel in the form of a substance selected from the classconsisting of metallic cobalt, cobalt oxides, cobalt metal carbonyls,and cobalt salts of organic carboxylic acids, at a temperature in therange of 175 to 375 C. under a pressure of from 50 to 3000 atmospheres,and thereafter separating an organic ester from the resultant reactionproduct, said process.being carried out in the absence of any othercatalyst for the said reaction.

12. A process for the preparation of methyl -10 propionate whichcomprises heating ethylene with carbon monoxide and methanol in thepresence of a catalyst which has been introduced into the reactionvessel in the form of a substance selected from the class consisting ofmetallic cobalt, cobalt oxides, cobalt metal carbonyls, and cobaltsaltsof organic carboxylic acids, at a temperature in the range of to375 C. under a pressure of from 50 to 3000 atmospheres, and thereafterseparating methyl propionate from the resultant product, said processbeing carried out in the absence of any other catalyst for the saidreaction.

13. A process for the preparation of ethyl propionate which comprisesheating ethylene with carbon monoxide and ethanol in the presence or acatalyst which has been introduced into the reaction vessel in the formof a substance selected from the class consisting of metallic co' balt,cobalt oxides, cobalt metal carbonyls, and cobalt salts of organiccarboxylic acids, 'at a temperature in the range of 175 to 375 C. undera pressure'of from 50 to 3000 atmospheres, and thereafter separatingethyl propionate from the resultant product, said process being carriedout in the absence of any other catalyst for the said reaction.

14. A process for the preparation of a polyhydric alcohol propionatewhich comprises heating ethylene with carbon monoxide and a primarypolyhydric aliphatic alcohol in the pressence of a catalyst which hasbeen introduced into the reaction vessel in the form of a substanceselected from the class consisting of metallic cobalt, cobalt oxides,cobalt metal carbonyls, and cobalt salts of organic carboxylic acids, ata temperature in the range of 175 to 375 C. under a pressure of from 50to 3000 atmospheres, and thereafter separating the polyhydric alcoholpropionate from the resultant product, said process being carried out inthe absence of any other cata lyst for the said reaction.

15. A process for the production of esters of organic carboxylic acidswhich comprises heating a non-aromatic hydrocarbon containing olefinicunsaturation with carbon monoxide and a primary aliphatic alcohol in thepresence of a catalyst which has been introduced into the reactionvessel in the form of a substance selected from the class consisting ofmetallic cobalt, cobalt oxides, cobalt metal carbonyls, cobalt salts oforganic carboxylic acids, at a temperature in the range of 175 to 375 C.under a pressure of from 50 to 3000 atmospheres, and thereafterseparating an organic ester of a carboxylic acid from the resultantproduct, said process being carried out in the absence of any othercatalyst for the'said reaction.

16. A process for the production of esters of organic carboxylic acidswhich comprises heating a non-aromatic hydrocarbon containing olefinicunsaturation with carbon monoxide and methanol in the presence of acatalyst which has been introduced into the reaction vessel in the formof a substance selected from the class consisting of metallic cobalt,cobalt oxides, cobalt metal carbonyls, and cobalt salts of organiccarboxylic acids, at a temperature in the range of 175 to 375 C. under apressure of from 50 to 3000 atmospheres, and thereafter separating anorganic ester of a carboxylic acid from the resultant product, saidprocess being carried out in the absence of other catalysts for the saidreaction.

17. A process for the production of esters of organic carboxylic acidswhich comprises heating a non-aromatic hydrocarbon containing olefinicunsaturation with carbon monoxid and ethanol in the presence of acatalyst which has been introduced into the reaction vessel in the formof a substance selected from the class consisting of metallic cobalt,cobalt oxides, cobalt metal carbonyls, and cobalt salts of organiccarboxylic acids, at a temperature in the range of 175 to 375 C. under apressure of from 50 to 3000 atmospheres, and thereafter separating anorganic ester of a carboxylic acid from the resultant product, saidprocess being carried out in the absenc of other catalysts for the saidreaction.

18. The method for preparing methyl 4-oxohexanoate by reacting ethylene,methanol and carbon monoxide at a pressure within the range of 1500 to8500 atmospheres in accord with the equation REFERENCES CITED Thefollowing references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 1,979,717 V8.11 NOV. 6, 1934OTHER REFERENCES Intelligence Division Report No. 4149, Advancg: inAcetylene Chemistry," pp. 20-26, Mar. 24,1 5.

1. A PROCESS FOR THE PRODUCTION OF ESTERS OF ORGANIC CARBOXYLIC ACIDSWHICH COMPRISES HEATING A NON-AROMATIC HYDROCARBON CONTAINING OLEFINICUNSATURATION WITH CARBON MONOXIDE AND A PRIMARY ALCOHOL AT A TEMPERATUREIN THE RANGE OF FROM 150* TO 500* C., UNDER A PRESSUR OF AT LEAST 50ATMOSPHERES, IN THE PRESENCE OF A CATALYST WHICH HAS BEEN INTRODUCEDINTO THE REACTION MIXTURE IN THE FORM OF A SUBSTANCE SELECTED FROM THECLASS CONSISTING OF METALLIC COBALT, COBALT OXIDES, COBALT METALCARBONYLS, AND COBALT SALTS OF ORGANIC CARBOXYLIC ACIDS, AND THEREAFTERSEPARATING FROM THE RESULTING MIXTURE AN ORGANIC CARBOXYLIC ESTER FORMEDBY THE ENSUING REACTION BETWEEN THE SAID HYDROCARBON, CARBON MONOXIDE,AND PRIMARY ALCOHOL, THE SAID PROCESS BEING CARRIED OUT IN THE ABSENCEOF ANY OTHER CATALYST FOR THE SAID REACTION.